Secondary clock



M.`D. METCALFE. SECONDARY CLOCK.

APPLICATION FILED MAR. I. 1920.

Patented Oct. 17, 1922;

v 2 SHEETS-SHEET l.

M. D. METCALFE.

SECONDARY CLOCK. AfPLlcAUoN FILEDMAR.|,1920.

1,432,566. 'Patented oct. 17,1922.

2 SHEETS-*SHEET 2.

Patented Oct. 17, 1922.

UNITED STATESl PATENT OFFICE.

MORTIMER D. METCALFE, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO GEORGE SEEBER, SR., OF ELIZABETH, NEW JERSEY. l

SECONDARY CLOCK.

Application filed March 1, 1920. Serial No. 362,383.

TocZZ whoml t lmay concern:

Be it known that l, MORTIMER D. Mirr- GALFE, a citizen of the United States, and a resident of N ewYork city, New York County,.New York State, have invented certain new' and useful Improvements in Secondary Clocks, of which the following is a specification.v f

The principal object of this invention is to provide a novel drive mechanism for intermittently operating mechanical devices, particularly electrical secondary clocks which are in circuit with master clocks and are driven by electrical mechanisms energized at regular intervals by the current flowing through a circuit which is made and broken by the master clock. Such clocks are well known and are adapted to be put to' a great variety of uses, as in office buildings,

schools, hotels, public buildings of all kinds,

and in private dwellings.

An objectionable feature of clocks of this character heretofore designed or suggested is that a mechanical sound is made whenever the electrical driving mechanism is operated.

This sound is sometimes caused by an armature oscillating between definite stops, sometimes by the clicking of pawls moving on ratchets, and sometimes in other ways. It

is obvious that where quiet is desired, as

for instance in hotel sleeping` rooms, in

schools, and in private dwe lings, these sounds, however faint, are irritating to the occupants of the room.

The present invention provides a noiselessly operating electrical apparatus, particularly useful for driving clocks, having no parts moving between mechanical stops, and iaving no portion or part the operation of whichmay result in objectionable sounds.

A further object of the invention is to provide an apparatus of this class having a minmium number of parts, in Awhich the parts are of simple character, which is readily accessible for cleaning and oiling, and which is of small size, rendering it conven-` ient for wall clocks, desk clocks, mantel clocks, tower clocks, or clocks for any special purpose.

provide a secondary electrical clock having two oppositely directed faces which are A further object of the invention is to adapted to be placed in a partition between two adjoining rooms and to have one face in each room, the hands of the clocks being mounted upon concentric shafts so that the clock faces are exactly opposite each other.

Another object of the invention is to pro-- vide a secondary clock which may be either a single or double faced clock, and which has in either instance a minimum number of parts enabling it to be made cheaply and easily, to be installed in small space, and enabling it to be cleaned and repaired conveniently. y

The invention will be disclosed as applied to a wall clock having dials in each of the two adjoining rooms but it will be under- -stood that vthe invention is not limited to this particular use but may be applied in many different ways. Also the present improved driving mechanism is described as applied to clock gearing with whichit may be advantageously used, but it will be understood that the silent drive may be used in connection with other types of clocks and with other mechanisms. One form of the invention will be described herein and il,- lustrated in the accompanying drawings in which:

Figure l is a central vertical section through a double faced clock showing the faces and the clock gearing;

Figure 2 is a section along the line 2 2 of Figure l, part of the gearing being omitted for the sake of clearness;

Figure 3 is a longitudinal sectional View through the mercury tube, which comprises a portion of the drive mechanism;

Figure 4 is a reduced side view clock, the faces being omitted;

Figure 5 is a section on the line -of Firure l;

Figure 6 is a view of part of the drive of the mechanism, as illustrated in Figure 5, the.

mercury tube being shown in a different po` sition; and

Figure 7 is a topview of the clock.

The various shafts upon which the moving members are mounted are supported at their ends in similar parallel side plates 10, con-k nected at their corners bv rods ll. Extending horizontally through suitable openings in plates l() and rotatably mounted therein,

are the main shaft 12 and the countershaft 13. On thel main shaft are supported the main elements of the hand operating gearing and on the countershaft are mounted the elements of theelectrical drive mecha.. nism for operating this gearing.

This electrical drive mechanism,comprises essentially a Zshaped armature 14rrigidly secured to the countershaft 13 and lying be tween the opposed pole pieces 15 of the twocoil electro-magnet 1G. Also rigidly mounted on this shaft is a mercury tube 17, the axis of which makes an acute angle with the axis of the main or central portion of the armature, as clearly illustrated in Figures 5 and 6. A quantity of mercury within the closed tube maintains it normally in the position shown in Figure 5 with its axis vertical, but when the magnets 16 are energized the armature is moved to a position in which the longitudinal axis through its main portion assumes a horizontal position as shown in Figure G, thereby rotating the shaft, cansing the mercury tube 17 to assume an inclined position., as shown in Figure 6. rllhe curved wings 14 of armature 111 are for the purpose of insuring that the armature rotates in the proper direction when lthe magnets are energized, this direction being clockwise as indicated by the arrows in lF ures and G.

After the tube has been rotatedinto its inclined positionthe mercury uf'illinaturally run from the higher to the lower side, where it will exert, due to the in'liuence of gravity, a force tending to rotate the tube, armature and shaft into a vertical position exactly 180o from their starting point, and as soon asthe magnets 16 are deenergized by the circuit through the master clock being opened, the tube will rotate to this position.

In order to prevent oscillation of the tube after its rotation through 180, which will undesirably oscillate the hands of the clock, means is provided for retarding thefiow of the mercury to the lower end ofthe tube after the magnet has been energized and the tube brought to its inclined position. This retarding means prevents the weight of the mercury from exerting 'immediately a maximum torque about the countershaft, which will be the case if the descent of the mercury from the high end to the low end is unimpeded, and might result in the tube oscillating when the magnets were cleeneigized. For this purpose valves 1S which open toward the shaft 13 are provided in thel cury tube, each of these valves 1khavingl a' restricted opening 1 9. The obvious effect of these valves is to permit the rapid flow of the mercury from the high end of the tube across the axis of the shaft 13, but prevents its immediate passage to the lower end of the tube. These valves are preferably made of liber or rubber. liy allmvingthe mercury to pass only gradually into position where it will exert a maximum torque tending to rotate the shaft, it has less tendency to overrun the center of gravity when the magnets are deenergized, and to thereby cause oscillation of the shaft and the clock hands. The two-coil n'iagnet 16 is supported from the four rods 11 by vUshaped members 20 preferably of sheet metal, the positions of the U-shaped members on the rods 11 being determined by the spacing members 21 and 22.

lt is desirable in the operation of seoondary electric clocks that the hands be moved forward at least once each minute, and in the operation of the present clock it is contemplated that the coils will be excited by the master clock at minute intervals, thereby causing a complete rotation of the shaft 13 once each two minutes. Gearn ing connecting the shaft 1/1 to the hands of the clock is therefore designed in this instance to nrove the 4hands forwardly the proper distance, that is, one minute space for the minute hand, each time the shaft lil rotates through 180".

In the drawings the minute hands are indicated at 23 and 24 respectively and the hour hands at 25 and 2G respectively. The

Vminute hand 23 is mounted directly on the shaft 12 and connecting the shafts 12 and 18 is a train of gearscomprising gears 27, 28, 29 and 230, the gears 27 and Il() being mounted on and rotatable with shafts 1S and 12 re spectively. Gears 28 and 29 are secured to gether and are mounted upon a short shaft 31 projecting from the plate 1l). This gearing connects the shaft 13 to the shaft 12 with a to 1 reduction, so that as the shaft 13 rotatesv 18()o each minute the shaft 1 2 will rotate each minute, which is the proper angle of advancement for the minute hand The hour hand 25 is mounted upon av sleeve 32 which sleeve is` driven from the shaft 12 by reduction gearing of the usual construction, the gears comprising this train indicated at 33, 34, 35 and 36 in the drawings. y

Inasmuch as the hands 24 and 2G ou the opposite clock faces must be rotated in a direction opposite to the direction of rota tion. of the hands 23 and 25, reversing gearing must be utilized. yThe large' gear wheel 30 which is rigidly mounted on the shaft 12 is provided on one side with a crown gear 37 and, rigidly mounted upon the sleeve 3S which supports the minute hand 2li is a similar and oppositely facing crown gear 39. Interposed between the crown.

gears 37 and 39 is a frameor yoke 40 supported upon the shaft 12 and short shafts 4-1 and 4t2- extending from the plate 10. This frame 4l() carries pinions 43, which mesh with the teeth of crown gears 37 and 39. lnasmuch as the pinions Lit?) are not rotatable around the shaft 12, the' motion of the crown gear 37 in one direction causes the crown gear 39 to move in the opposite direction and at an equal speed, which speed is the speed of shaft 12, and it is therefore apparent that the minute hand 24 which is mounted upon the sleeve 38,v

which in turn supports the gear 39, will be moved at the exact speed of shaft 12 and the minute vhand 23 but in the opposite direction.

Also rigidly mounted on the sleeve 38 is a gear'44 meshing with a large gear 45 mounted on the shaft 41'. Secured to the gear 45 and rotatable on the shaft 41 is a gear 46 .which meshes in turn with` gear 47 rigidly mounted upon asecond or `outer sleeve 48. This series of gears 44, 45, 46 and47 comprises a reduction train Whereby the outer sleeve 48 is operated at onetwelfth the speed of the minute sleeve 38. Suitable spacing members may be utilized to maintain the various gears in proper position, but for the sakev of clearness said devices have been omitted from the drawings.

From theI above description the operation of the clock will be apparent. The mercury tube is rotated .by means of the armature 14 through an angle of between 900 and 180o once each minute' and as soon as the electrical circuit through the electro magnets is broken at the master clock, the mercury, which has in the meanwhile changed position from the highv to the low end of the tube, will, by force of gravity, complete the rotation of the tube and shaft 13 through 180. Through the gearing described the minute handsy are advanced thereby one minute, and the hour hands onetwelfth of. that amount. f

The mechanismhas no parts which' are capable of producing mechanical sounds, however faint, in operation. No pawls are necessary, no springs, and no means for positively limiting the movement of the rotating armature, inasmuch as the mercury tube is incapable of assuming any positiony other than a vertical one when the coils are deenergized thereby advancing the hands of the clock the `exact distance desired at each movement. It is obvious that changes may be made in the form and structure of the invention and I do not limit myself to the vexact form shown and described. For example, some other substance or body might be used as a shifting Weight instead of the mercury utilized and other means might be utilized for retarding the movement of the shifting Weight.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. Mechanism for intermittently rotating a shaft or other rotatable element comprising in combination, a rotatable member, means for rotating' said member through an angle less then 180o, and second means supported by said member for continuing the rotation of said member to a position substantially 180 from the point at which said first means became active. f Y

2.xl\lechanism for intermittently rotating a shaft or other rotatable element comprising inv combination, a rotatable member, means for rotating saidmember through an angle less'than 1800, and second -means comprising a shiftable weight supported by said member' for continuing the rotation of said member to a position substantially 180o from the point at which said first means became active.

8. Mechanism for intermittently rotating a shaft or other rotatable element comprising in combination, a. pivoted rotatable member, means for rotating said member through an angle less than 180o, and second means comprising a weight supported on said rotatable member and movable thereon from one side of its pivotaly point tothe other, for oontinuing the rotation of said member to a position substantially 1800 from the point at ywhich said first vmeans became active.

4. Mechanism for intermittently rotating ashaft or other rotatable element comprising in combination, a rotatable member,- means for rotating said member throughk an angle less than 180", and gravity actuated second means for ntinuing the rotation of saidV member to a position substantially 180o from the point at, which said first means became active. f

5. Mechanism for intermittently rotating a shaft or other rotatable element comprising in combination, a rotatable member, means for rotating said member, a pivotally mounted tube, means for rotating said tube through an angle less than 180", and a weight Within said tube adapted to move underthe influence of gravity. fromy one side of said pivotal point to the other upon the initial movement ofv said member, for continuing the rotation of said .member'to a position substantially 1800 from ythe pointy at which said first means became active.

6. Mechanism of the class described, comprising in combination` a rotatable shaft, a member fixed on said shaft, electrical means for rotating said shaft through an angle less than 180, and vsecond means for continuing the rotation of said member to a position substantially 180o from the point at which said first means became active.

7. Mechanism of the class described comprising in combination, a shaft,a member mounted on said shaft, electrical means for rotating said shaft and member through an angle less than 1800, said means including an armature mounted on said shaft, and second means for continuing the rotation `iter rotatingsaid member through an angle less than i800, and gravity actuated secondary.. means :tor `continuing` the rotation ot said member to a position substantially 1800 'from the point at` which said lirst means becomes active. i v

9. ln an electrically operated secondary clock, gearingineans for intermittently operating said gearing, said means including,` a rotatable mei ber, electrical means -tor rotating said member 'through an angle less than 1800, and gravity actuated secondary means ior continuing` the rotation oi said member to a position substantially 180 from the point at which said electrical means becoines active. Y i

vl0. Mechanism tor intermittently rotating a shaft or other rotatable element including` a pivotally mounted tube, means 'for rotating said tube through an angle less than i800, a weight `within said tube adapted to lnove under the influence olf gravity from one side ot said pivotal point to the other when said tube has been rotated, vforcentinuing the rotation ol' said tube to a posi tion substantially 1800 trom the point at which the rotating` means became active, and means for retardingthe movement .ot the 'Weight toward the lower end ot `.the tube after it has crossed the pivotal point, ttor the purpose set forth. U

.11. Mechanism for intermittently rotating; shaft or other rotatable element including a pivotally mounted member, means 'lior rot-ating said member through an angle less than 1809, a Weight supported on said member and adapted to move under the influence ot' gravity from one side oit the pivotal pointl kto the other when said memberhas been rotated,`tor continuing; the rotation of said tube to a position substantially 180o -trom the point atwhich the rotating means became active, and means tor retarding the movement ot the Weight toward thevloiver `end of the member at'ter ithas crossed the pivotal point,:ior the purpose set forth. 1

l2. ltlechanism Yfor intermittently rotating; shatter other rotatable element, includinga lliivotally mounted tube, means for rotating the tube through an angle less than 180", :mercury in the tube adaptedto move under the in'liuence ot gravity from one side of the pivotal point to the other-When the tube has been rotated, for continuing the rotation ot said tube to a position substantially 1800 from vthe position at which the rotating means became active, and means for retard,- ing;` the movement ot the mercury toward the lower end ot the tube atter it has crossed the pivotal point, tor the purpose set torth. 18. Mechanism lor intermittently rotating a shatt or other rotatable element', including.;- a pivotally mounted tube, means 'tor rotatingv the tube through an angle less than 180'", mercury in. the tubeadapted to move under the influence oit gravity :from one side of the pivotal point to the other when the tube has been rotated, lor continuingv the rotation oi said tube to a position substantially 1800 'from the` position at which the' rotating means became active, and valve means ttor retarding the movement ot the mercury tou'ard the loiver end oit thetube after it has crossed the pivotal point, ifor the forth. v

lll. Mechanism 'for intermittently rotating a shalt or other rotatable element, including a pivotally mounted tube, meansl ior rotatM ing the tube through an angle less than 1800, mercury in the tube adapted to move under the intluence oit gravity'irom one side o'l the pivotal point to the other `when the tube has been rotated, for continuing; the rotation ot said tube to a position substantially 1800 from` the position at `which ,the rotating means became active, andmeans comprising an Vinwarddy openingl valve having a pertoration therein, `adjacenteach end ot the tube, t'or retarding the movement olf the mercury toward theloiver endet the tube ailter it has crossed the pivotal point, -ior the purpose set purpose set y 

